The invention generally relates to aerial work platforms and, in particular, to a computer based control system for an aerial work platform having various safety and control features.
With regard to the control of aerial work platforms, it is known to use a control panel which operates the aerial work platform whenever a manually activated switch, such as a foot switch, is held in a depressed position. In the event that the switch is released, the control panel becomes inactive. Alternatively, the aerial work platform may contain selectively placed switches which must be held in place by the operator. These switches interrupt power when an operator leaves the operating station and takes a position remote from the switches such that the switches are no longer held in place by the operator.
There is a need for a computer based control system for an aerial work platform which allows operation of the platform by an operator at its base or on the platform and which includes safety features and interlocks preventing inadvertent or unsafe operation of the aerial work platform.
It is an object of this invention to provide a microprocessor controller for an aerial work platform which has ground and platform controls linked by a controller area network for transmitting input commands issued by an operator at the platform control or at the ground control to a controller so that operation of the boom can efficiently and safely occur from either control.
It is also an object of this invention to provide a controller in conjunction with sensors for an aerial work platform which restrict or minimize operation of the platform in certain positions beyond a predefined three-dimensional envelope to enhance safe operation of the platform within a safe envelope.
It is also an object of this invention to provide such a controller which provides automatic retraction of the platform to maintain the platform within the safe envelope and which automatically retracts the boom in response to certain operator commands which attempt to operate the boom outside the safe envelope.
It is an object of this invention to provide a computer based electronic control for an aerial work platform which ramps boom movement in any direction as applicable to provide for smooth and safe operation of the boom and its movement.
It is also an object of this invention to provide such a controller which executes multiple boom movements either sequentially and/or simultaneously in an efficient, safe and smooth manner.
It is another object of this invention to provide such an aerial work platform which has sensors and software for preventing inadvertent or unsafe operation of the boom and for saving power.
In one form, the invention is an aerial work apparatus comprising a base, a platform, a boom connecting the platform and the base, a hydraulic system for moving the boom sections and a boom control. The boom control controls the hydraulic system in response to operator input to move boom sections in accordance with the operator input. The boom control comprises a first control module on the base responsive to an operator for providing boom motion commands for causing the boom to move in a desired direction; a second control module on the platform responsive to an operator for providing boom motion commands for causing the boom to move in a desired direction; and a controller area network interconnecting the first module control module and the second control module.
In another form, the invention comprises an envelope controller suitable for use with an aerial work platform having a boom comprising a plurality of boom sections, a hydraulic system for moving the boom sections, a work platform supported by the boom, a base supporting the boom, a boom control for providing a boom control signal to the hydraulic system, the boom control signal controlling the hydraulic system to control motion of one of the plurality of boom sections. The envelope controller comprises a position detector subroutine or circuit for detecting a position of the boom sections or work platform relative to a position of the base; and a position limitation subroutine or circuit for inhibiting the boom control signal being provided to the hydraulic system when the position detector subroutine or circuit indicates that the detected position of the boom sections or work platform relative to the position of the base will exceed an envelope limit whereby the envelope controller limits the position of the boom sections or work platform relative to the position of the base to within a predefined region.
In another form the invention comprises an aerial work apparatus comprising a base; a platform; a boom having a plurality of boom sections connecting the platform and the base; a hydraulic system for moving the boom sections; and a boom control for controlling the hydraulic system in response to operator input to move the boom sections in accordance with the operator input. The boom controller comprises a boom section select switch response to operator input for selecting one of the plurality of boom sections to be moved; a boom motion input switch response to operator input for providing a boom direction signal indicative of a desired direction of boom motion for the selected boom section to be moved and providing a desired boom speed; and a boom ramping controller, responsive to the boom section select switch and boom motion input switch, for controlling the hydraulic system to move the selected boom section in accordance with the boom direction signal, the boom ramping controller adapted to cause the hydraulic system to move the selected boom section at a varying velocity which does not exceed a preset maximum velocity so that the boom accelerates at a preset rate from zero velocity to the desired velocity.
In another form the invention comprises an aerial work apparatus comprising a base; a platform; a boom having a plurality of boom sections connecting the platform and the base; a hydraulic system for moving the boom sections; and a boom control for controlling the hydraulic system in response to operator input to move the boom sections in accordance with the operator input. The boom control comprises a boom section select switch responsive to operator input for selecting only one of the plurality of boom sections to be moved; a boom motion input switch responsive to operator input for providing a boom direction signal indicative of a desired direction of boom motion; and a boom controller responsive to the boom section select switch and the boom motion input switch for controlling the hydraulic system to effect boom motion, the boom controller adapted to cause the hydraulic system to sequentially move the boom from one operator requested movement to the next operator requested movement or to simultaneously move the boom in a second direction in response to an operator requested movement while the boom is moving in response to a previous operator requested movement.
In another form the invention comprises an aerial work platform comprising a plurality of boom sections; a boom control for providing a motion output signal for controlling a motion of one of the plurality of boom sections in response to input from an operator to the boom control; and a timer subroutine or circuit. The timer subroutine or circuit comprises a safety subroutine or circuit for monitoring operator input requesting boom movement and for preventing the boom control from responding to operator input requesting boom movement in the event that there has been no operator input requesting boom movement for a first time period; and a power saver subroutine or circuit for monitoring operator input to the boom control, the power saver subroutine or circuit deactivating the boom control when the power saver subroutine or circuit detects no operator input to the boom control for a second time period.
In another form the invention comprises an aerial work apparatus comprising a base; a platform; a boom connecting the platform and the base; a hydraulic system for moving the boom sections; and a boom control for controlling the hydraulic system in response to operator input to move boom sections in accordance with the operator input. The boom control comprises a microprocessor having inputs for receiving operator inputs and having outputs providing output signals which are a function of the operator input provided to the microprocessor input, the hydraulic system being responsive to the output signals; a first control module on the base responsive to an operator for providing first boom motion command signals for causing the boom to move in a desired direction, the first boom motion command signals being supplied to the inputs of the microprocessor; and a second control module on the platform responsive to an operator for providing second boom motion command signals for causing the boom to move in a desired direction, the second boom motion command signals being supplied to the inputs of the microprocessor.